Ion-imprinted polymeric nanoparticles for fast and selective separation of lanthanum(III)

Modern Rare Earth Imprinted Membranes for the Recovery of Rare Earth Metal Ions from Coal Fly Ash Extracts

The need to identify secondary sources of REEs and their recovery has led to the search for new methods and materials. In this study, a novel type of ion-imprinted adsorption membranes based on modified chitosan was synthesized. Their application for the recovery of chosen REEs from synthetic coal fly ash extracts was analyzed. The examined membranes were analyzed in terms of adsorption kinetics, isotherms, selectivity, reuse, and their separation abilities. The experimental data obtained were analyzed with two applications, namely, REE 2.0 and REE_isotherm. It was found that the adsorption of Nd3+ and Y3+ ions in the obtained membranes took place according to the chemisorption mechanism and was significantly controlled by film diffusion. The binding sites on the adsorbent surface were uniformly distributed; the examined ions showed the features of regular monolayer adsorption; and the adsorbents showed a strong affinity to the REE ions. The high values of Kd (900-1472.8 mL/g) demonstrate their high efficiency in the recovery of REEs. After five subsequent adsorption-desorption processes, approximately 85% of the value of one cycle was reached. The synthesized membranes showed a high rejection of the matrix components (Na, Mg, Ca, Al, Fe, and Si) in the extracts of the coal fly ashes, and the retention ratio for these Nd and Y ions was 90.11% and 80.95%, respectively.

Magnetic N-rich carbon nitride framework material for the high selectivity extraction and determination of La(III)

A novel magnetic C₃N₅ framework material (Fe₃O₄/C₃N₅) was developed as a high selectivity extractant for La(III) determination in food samples. The Fe₃O₄/C₃N₅ material was synthesized by thermal deammoniation method and has larger surface area (100.3 m² g^-1) and more effective adsorption sites compared with that of individual C₃N₅ material (19.4 m² g^-1). It was proved that Fe₃O₄/C₃N₅ material displayed excellent selectivity and adsorption capacity for La(III). In addition, adsorption isotherm and kinetic data indicated that La(III) adsorption based on Fe₃O₄/C₃N₅ material is a monolayer adsorption which is compatible with Langmuir model and follows a pseudo-second-order kinetic equation. By using Fe₃O₄/C₃N₅ material as extractant, an analytical method was established with low limits of detection (3σ, n = 6) of 10.4 μg L^-1, reasonable recoveries ranged from 86% to 106% and good precision with the RSD less than 10.7%. The analytical method was further applied to the determination of trace La(III) in food sample. It evinced that the concentration of La(III) in sea fish is 13.2 μg kg^-1 and the content of ¹³⁸La is 0.138 μg kg^-1, which is 1.03% of total La(III).

Ion-Imprinted Polymers: Synthesis, Characterization, and Adsorption of Radionuclides

Growing concern over the hazardous effect of radionuclides on the environment is driving research on mitigation and deposition strategies for radioactive waste management. Currently, there are many techniques used for radionuclides separation from the environment such as ion exchange, solvent extraction, chemical precipitation and adsorption. Adsorbents are the leading area of research and many useful materials are being discovered in this category of radionuclide ion separation. The adsorption technologies lack the ability of selective removal of metal ions from solution. This drawback is eliminated by the use of ion-imprinted polymers, these materials having targeted binding sites for specific ions in the media. In this review article, we present recently published literature about the use of ion-imprinted polymers for the adsorption of 10 important hazardous radionuclides-U, Th, Cs, Sr, Ce, Tc, La, Cr, Ni, Co-found in the nuclear fuel cycle.

Microfluidic array surface ion-imprinted monolithic capillary microextraction chip on-line hyphenated with ICP-MS for the high throughput analysis of gadolinium in human body fluids

A novel method by hyphenating chip-based array ion-imprinted monolithic capillary microextraction with ICP-MS was proposed for the online analysis of trace Gd in biological samples.